Slide scale



ANov. 22, 1932. F. B. HUFFMAN SLIDE SCALE Filed Oct. '7, 1930 mvENToR y BY ATTORNEY Patented Nov. 22, 1932 UNETED `STATES FREDERICK B. HUFFMAN, F lSIPOKANEJ WASHINGTON SLIDE SCALE Application filed October 7, 1930. Serial No. 486,539.1.

My present invention relates to an improved slide scale for useV inV combination with a` T square, as employed by draftsmen, engineers, and others. The primary 5. object of the invention is the provision of an adjustable measuring instrument com` bined for use with the blade of the T-square in such manner that plans may be pointed or plotted; measurements for dimensions may readily be made; and both perpendicular and horizontal lines be accurately drawn, the perpendicular lines being drawn by the use of a triangle. A protractor or other geometrical instrument may also be used in combination with ll"-square and slide scale, as will be apparent to anyone skilled in the use of such instruments. v

In carrying out my invention the instrument may be used as a combined device, the T-square may be used for the performance of the functions of the usual or customary T-square, and the slide scale may be utilized for solving problems where the customary slide scale is needed.

The invention consists essentially in the combination with the blade of the T-square, of an adjustable slide scale and a complementary iiXed scale, and in other combinations and arrangements of parts related thereto, as will hereinafter be more fully set forth and claimed.

In the accompanying drawing I have illustrated one complete example of the physical embodiment of the invention wherein the parts are combined and arranged according to the best mode I have thus far devised for the practical application of the principles of my invention.

Figure l is a plan view of a T-square, partly broken away for convenience of illustration and showing the physical embodiment of my invention.

Figure 2 is an enlarged transverse sectional View at line 2-2 of Figure l.

tion of the instrument, showing by dotted lines the manner of releasing the removable slide scale from the T-square, and for applying the slide scale to the blade of the T- square.

Figure 3 is an enlarged plan view of a por- Figure 4 is a view at the back edge of the l instrument, as at line l--C` of Figure 1.

In the physical embodiment of my invention as illustrated in Figure l I employ the well known draftsmans T-square havingA the head l and blade 2, with the front ruling edge 3 andbaclr edge 4, all of which are fashioned of suitable material, Vand the T -square is adapted for the customary uses of-such an instrument. 60 In Converting the T-square for use incarryingout my invention'I utilize a" guide block 5 of hard wood, metal, or other appropriate material, and this block is fas-tened in a mortise 6 in the blade, a. dovetail edge 65 Y 7 being provided on the block for insuring a rigid and stable arrangement ofthe'block, and the latter is fastened, as bygluing (orV in other suitable manner)v in position. The dovetailed bottom edge of the block isiiush 795 with the bottoni of 'the blade, butjthe upper or top edge of the block projects above the upper face of the blade, and asshownythe block extends longitudinally of the blade and parallel with the front ruling edge 3 of '72; the blade. o

Adjacent to the back edge" of `the blade =a scale plate 8 is fastened-to' the blade-by rivets, screws, or other fastening devices a's-9, and this plate or strip has affront guide edge 9', gi) parallelwith `the lfront ruling edge of the blade, and ofV course vparallel with the-guide The pla-te or strip 8, through .the use'o'f its guide edge 9, guideslthe movem'erit of a 85 siideplate 10,'in combination with thefguide bloeit' At the guide edge 9" of the fixed piateand 4along the" back edge' of the slide plate a Vernier scalel is arranged 'fornieasuring fractionfparts, and this Vernier-scale is adapted for use with a linear scale y(twelve inches) laid out on the front ledge of the slide pmu-,1o. i

Y 'ihe front or working `edgeV of theradj'ustl able, slidable scalev plate coincides, approximately, with the front or ruling yedge ofitl'ie blade, andv this inch-scale maybe used VTVfor Y laying outV dimensions and plotting plans, lp. by-means of a triangle, protractor, or other instrument adapted for use with the straight edge or ruling edge of the blade.

The slide plate l0 is fashioned with a longitudinal slot 12, terminating near the ends of the plate, and the slot lits over the guide block 5 in such manner as to insure a neat and close lit between the slide plate, its vguide bloclrand the guide plate 8.. In its upper face the slide plate may be provided with depressions as 13 to receive the point of a pencil, as a hard drawing pencil, and by means of the pencil a close adjustment of the slide plateV and scale may be secured.k

The slide plateis held down in proper position on the blade by means of a pair of spaced, spring lingers let mounted onV the ends of the block, and with their opposite `ends bearing on the slide plate with suti'icient Vtension as to hold the plate to the blade, but at'the same time permit sliding of the plate.

These resilient bla-des or spring lingers are mounted in longitudinally extending slots or sli-ts 15 opening at the opposite ends of the guide block, and rivets or pins as 16 secure the blades in their slots and at the same time actas pivots for the blades. The slits or slots are of suliicient length to permit the blades to be swung on their pivots with their long axes 'parallel with vthe length of thebloclr, as indicated in Figur'el, and when so turned or swung, 'the slide plate 1s free to bevremoved from theblade. Y

iFor clamping the slide plate in adjusted .positionafter it has been properly adjusted p for the desired scale or measurements I use a pair ofresilient clamps 17 or spring blades l with the ruling edge of the blade, resilient means mounted on the block for pressing the plate against the blade, a guide plate back of the slide plate and a Vernier scale on adjoining edges of the slide alate and guide plate, and means on the gui e plate for frictionally engaging the slide plate to retain the latter inadjusted position. i Y

2. The combination with a straight edge blade and a guide block rigid therewith, and a tiXedY guide plate on the blade, of a slotted slide plate co-acting with the guide block and said fixed plate, said guide plate and slide plate having a Vernier scale on adjoining edges, resilient means on the block forfretaining the slide `plate against the blade, and

means on the guide plate for frictionalengagement with the slide plate'forretaining the latter in adjusted position. Y

y 3. The combination with a blade of a T- square, a slitted guide bloclrrigid therewith, and a guide plate rigid with the blade and spaced from the block, of a slotted slide plate embracing the block and avernier scale on adjoining edges ofthe guide plate and slide plate, pivotal resilient blades mounted in the slitted guide block. for engaging, said .slide plate, and spring clamp blades mounted on the guide plate for rictionallyengaging the slide plate. y In testimony whereof I alix mysignature.

FREDERICK B. HUFFMAN.-

TheclampsYo-r resilient blades are mounted on the fixed guide-plate, and for this purpose ,the latter has near itsends upwardly proj ecting studs or screws 18 over which the perj forated endsy of the clamps are litted, and i clamp nuts 19 on thescrews bear against the clamp blades and press them with varying degrees of tension against the slide plate to hold the latter in adjusted position while the instrument is being utilized. 1

From this vdescription taken in connection with' my drawing it will be apparent that I 'have provided an instrument that is comparatively inexpensive in cost of production and manufacture, but which may be used with facility, accuracy, and precision as a labor Y 'saving device for the draftsman, engineer,

and' others accustomed to using suchfinstruments. Having thus fully` described my invention,

l i whatI claim as new and desire to secure by Letters Patent is zf y '1. The combination with v square and a guide block rigid therewith, of Va slotted plate having a scale edge coinciding the blade of a T- y "ilio- 

